1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
use std::ffi::{CStr, CString};
use std::ptr;
const PAM_PROMPT_ECHO_OFF: libc::c_int = 1;
const PAM_PROMPT_ECHO_ON: libc::c_int = 2;
const PAM_ERROR_MSG: libc::c_int = 3;
const PAM_TEXT_INFO: libc::c_int = 4;
const PAM_SUCCESS: libc::c_int = 0;
#[repr(C)]
struct PamMessage {
msg_style: libc::c_int,
msg: *const libc::c_char,
}
#[repr(C)]
struct PamResponse {
resp: *mut libc::c_char,
resp_retcode: libc::c_int,
}
type PamConvFn = unsafe extern "C" fn(
num_msg: libc::c_int,
msg: *mut *const PamMessage,
resp: *mut *mut PamResponse,
appdata_ptr: *mut libc::c_void,
) -> libc::c_int;
#[repr(C)]
struct PamConv {
conv: PamConvFn,
appdata_ptr: *mut libc::c_void,
}
type PamHandle = libc::c_void;
extern "C" {
fn pam_start(
service_name: *const libc::c_char,
user: *const libc::c_char,
pam_conversation: *const PamConv,
pamh: *mut *mut PamHandle,
) -> libc::c_int;
fn pam_authenticate(pamh: *mut PamHandle, flags: libc::c_int) -> libc::c_int;
fn pam_end(pamh: *mut PamHandle, pam_status: libc::c_int) -> libc::c_int;
}
pub trait Conversation {
fn prompt_echo(&mut self, msg: &CStr) -> Result<CString, ()>;
fn prompt_blind(&mut self, msg: &CStr) -> Result<CString, ()>;
fn info(&mut self, msg: &CStr);
fn error(&mut self, msg: &CStr);
}
pub struct Client<C: Conversation> {
handle: *mut PamHandle,
// Box the conversation so the pointer in PamConv remains stable.
conversation: Box<C>,
}
unsafe extern "C" fn converse<C: Conversation>(
num_msg: libc::c_int,
msg: *mut *const PamMessage,
resp: *mut *mut PamResponse,
appdata_ptr: *mut libc::c_void,
) -> libc::c_int {
let conv = &mut *(appdata_ptr as *mut C);
let count = num_msg as usize;
let responses = libc::calloc(count, std::mem::size_of::<PamResponse>()) as *mut PamResponse;
if responses.is_null() {
return libc::ENOMEM;
}
for i in 0..count {
let message = &*(*msg.add(i));
let c_msg = CStr::from_ptr(message.msg);
match message.msg_style {
PAM_PROMPT_ECHO_ON => match conv.prompt_echo(c_msg) {
Ok(s) => (*responses.add(i)).resp = libc::strdup(s.as_ptr()),
Err(_) => {
free_responses(responses, count);
return PAM_SUCCESS + 1;
}
},
PAM_PROMPT_ECHO_OFF => match conv.prompt_blind(c_msg) {
Ok(s) => (*responses.add(i)).resp = libc::strdup(s.as_ptr()),
Err(_) => {
free_responses(responses, count);
return PAM_SUCCESS + 1;
}
},
PAM_TEXT_INFO => conv.info(c_msg),
PAM_ERROR_MSG => conv.error(c_msg),
_ => {}
}
}
*resp = responses;
PAM_SUCCESS
}
unsafe fn free_responses(resp: *mut PamResponse, count: usize) {
for i in 0..count {
let r = &mut *resp.add(i);
if !r.resp.is_null() {
libc::free(r.resp as *mut libc::c_void);
}
}
libc::free(resp as *mut libc::c_void);
}
#[derive(Debug)]
pub struct PamError(pub libc::c_int);
pub type PamResult<T> = Result<T, PamError>;
impl<C: Conversation> Client<C> {
pub fn with_conversation(service: &str, conversation: C) -> PamResult<Self> {
let mut conversation = Box::new(conversation);
let c_service = CString::new(service).map_err(|_| PamError(1))?;
let pam_conv = PamConv {
conv: converse::<C>,
appdata_ptr: &mut *conversation as *mut C as *mut libc::c_void,
};
let mut handle: *mut PamHandle = ptr::null_mut();
let ret = unsafe {
pam_start(
c_service.as_ptr(),
ptr::null(),
&pam_conv,
&mut handle,
)
};
if ret != PAM_SUCCESS {
return Err(PamError(ret));
}
Ok(Client {
handle,
conversation,
})
}
pub fn authenticate(&mut self) -> PamResult<()> {
let ret = unsafe { pam_authenticate(self.handle, 0) };
if ret == PAM_SUCCESS {
Ok(())
} else {
Err(PamError(ret))
}
}
}
impl<C: Conversation> Drop for Client<C> {
fn drop(&mut self) {
if !self.handle.is_null() {
unsafe {
pam_end(self.handle, PAM_SUCCESS);
}
}
}
}
|
